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This Is Bugging Me!
LenGlover
Posts: 31,651
More than three-quarters of the nation’s colleges and universities now offer online classes, and about 23% of college graduates have taken a course online. 39% of those who have taken a course online believe that online courses provide the same educational value as one taken in person, a view shared by only 27% of those who have not taken an online course. At a coffee shop you overhear a recent college graduate discussing that she doesn’t believe that online courses provide the same educational value as one taken in person. What’s the probability that she has taken an online course before?
0.2079
0.1997
0.3014
0.1403
I have an answer which is wrong apparently but I don't understand why.
Can a maths whizz give the correct answer with an idiots' explanation as to why?
0.2079
0.1997
0.3014
0.1403
I have an answer which is wrong apparently but I don't understand why.
Can a maths whizz give the correct answer with an idiots' explanation as to why?
0
Comments
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Can't we just have a Would'Ya or Whose Rack?8
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I wish I could help with an answer, but I barely understand the question1
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I make it .1997. if that's right then i'll attempt the explanation..0
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Seriously Len, it's not worth worrying about.0
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redlanered said:
I make it .1997. if that's right then i'll attempt the explanation..
Correct! Why?redlanered said:I make it .1997. if that's right then i'll attempt the explanation..
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well then it will bug you and me both...0
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EH?0
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I said incorrect to your first answer.redlanered said:well then it will bug you and me both...
Your second one is correct so why?0 -
I'd say it was 0.14030
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I am with redlanered, I make it .1997 :-)1
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I said that too but it is incorrect and I don't know why hence the thread.stackitsteve said:I'd say it was 0.1403
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Len, stop going in Coffee Shops and listening to women's conversations. This isn't Sex & the City.5
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1 -
Say there are 100, 000 students in the world
23% have done a course online so 23,000. 39% of those (8,970) believe it has the same value, 61% (14,030) think it doesn't
77% (77,000) haven't done a course online. 27% (20,790) think it has the same value, 73% (56,210) don't
so there are 70, 240 who don't believe the courses have the same value. of those 14, 030 have done an online course
14, 030 is 19.97% of 70, 240 so 0.19970 -
OK, the explanation. We've met a 'non-believer' in the coffee shop.
Imagine there are 100 graduates: 23 of them have taken an online course, 77 haven't
Of the 23 who have taken an online course, 61% are 'non-believers' - that's 14.03 non-believers (23 x 61%)
Of the 77 who haven't taken an online course, 73% are non-believers - that's 56.21 non-believers (77 x 73%)
So of our 100 students, we have 70.24 'non-believers' (14.03 + 56.21). 14.03 of these have taken an online course, so the probability is .1997 (14.03 divided by 70.24)0 -
as to why Len & I might care, anything to take our minds off of yesterday...0
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Bang on the money rinarina said:Say there are 100, 000 students in the world
23% have done a course online so 23,000. 39% of those (8,970) believe it has the same value, 61% (14,030) think it doesn't
77% (77,000) haven't done a course online. 27% (20,790) think it has the same value, 73% (56,210) don't
so there are 70, 240 who don't believe the courses have the same value. of those 14, 030 have done an online course
14, 030 is 19.97% of 70, 240 so 0.19971 -
Yes, 19.97%.
she's either
a) taken a course and disagrees it offers the same value, or
b) not taken a course and disagrees it offers the same value.
The total probability that someone would disagree is that
a) There's a 23% chance she HAS taken a course, and of that a 61% chance she disagrees which is overall a 14.03% chance PLUS
b) There is a 77% chance she has not taken a course, and a further 73% chance she disagrees which is overall a 56.21% chance
So the the total probability is 70.24% of which 14.03% is that she has taken the course. 14.03% of 70.24% is 19.97%.
I dont feel I have explained this very clearly, but I have work to do.
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Thanks redlanered and Rina.
Your explanations both make sense.
After many years of not doing this stuff I've now remembered that read the question CAREFULLY is fundamental!!
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Thanks Idle Hans0
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I reckon she was lying anyway, graduates don't go in coffee shops
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Was this thread started as a cunning ruse to baffle any eavesdropping spanners?0
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For some monday evening entertainment, try putting this on the Millwall forum.0
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After Sundays fiasco, I'm struggling to put two and two together....................5?0
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Personally I'd argue we don't have enough information to answer the question accurately, as we don't know what proportion of the surveys were "don't know" rather than "agree" or "disagree", so we can't assume the "disagree" percentages were 61% and 73% of the relevant samples.
:-)0 -
How tall is she?0
